Compressor



April 16, 1935. B. s. AIKMAN 1,998,264

COMPRESSOR Filed July 50, 1932 Fipl. 6 O 45 a H 46 INVENTOR BURTONS.AIKMAN A TTORNEY Patented Apr. 16, 1935 PATENT "OFFICE g V ooMrREssonl Burton S. Aikman, Milwaukee, Wisg assignor to The Westinghouse AirBrake Company, Wilmerding, Pa a corporation of Pennsylvania; Y 7Application July30, 1932 SerialjNo. 6263501 14 mains; ci."230 z12)' Thisinvention relates to fluid compressors and particularly to fluidcompressors of the recipro cating piston type. v An object or" theinvention is to provide'a fluid compressor of the reciprocating pistontype wherein a single piston is utilized to'co'mpress fluid in two'stages during each cycle of operation or during a single revolutionofthe crankshaft driving the piston. y I

A further objectof the invention is toprovide a compact twostagecompressor which 'requires practically no more space or parts than isrequired for asingle stage compressor.

A further object of the invention is to provide a fluid compressorhaving theabove noted characteristics wherein provision is made forprecooling the fluid entering the compressor and for adequately coolingthe compressed fluid. during the progress of compression, therebyincreasin the eificiencyof thefapparatus. These and other objects of.the invention tha will be made apparent throughout the furtherdescription thereof are attained bymeans of the fluid compressorhereinafter described and illustrated in the accompanying drawing;wherein,

.Fig. t is a vertical sectional view of a fluid compressor embodyingfeatures of the invention; and w i Fig. 2is'a transverse sectional viewor the apparatus shown in Fig. 1, taken on the line 2I2 thereof. 7 l. Hl Referring to the drawing; the compressor come prises a crank casesection 3; a guidecylinder sec-c tion mounted thereon, a compressorcylinder section 5 mountedupon the guide-cylinder section, a headsection 6 mounted on the compres-' sion cylinder section and an intakesection '1' secured to the head section. 7

The crank case section 3 comprises a casing I 5;

part of which is shown, and which contains a crank chamber-J2.

V The casing also comprises an annular chamber i 3 for containing a,cooling fluid such as water which supplied to, the chamber in a mannerto be hereinafter described.- The l chamber 5 3 surrounds a circularopening Milli the case through which the piston rod l5 projects and intowhich the lower end of a guide cylinder itextends; the guide'cylinderconstitut ing an integral partof the casing H f-the guide cylindersection 4, which is secured to-theupper attaching face 53 of the casingH. p The guide cylinder casing I? is provided with a valve chamber 59containing'an outlet'jcheck valve device 2! of the disc type, whichcomprises a seat disc 22 thatis inserted in an opening-23 in,

the valve disc 48 and the flange 5| of a retaining the casing l1 andwhich is retained 'inas'semled 7 position we vretainingcage z l,threaded in an opening 25 in the casing l1 an'd which is aligned with anopening Win the outer wall of the casing |1 -through which the cagemaybe inserted. The 5 opening 20 is closed by a plate26 that may besecured to the casing ill bymeansof screws, not shown; I

yThe seat disc 2l2is' provided withfa series'of I ports 21 disposedin acircIe and which are adapted to be closed by a valve disc 28 thatisyieldingly held, in seated position by' ineansf-ofg'a spring129 that isdisposedbetween'the valve disc 28 and the flange 3! of a retainingwa'sher 32 that is at tached'to'the'seat disc 22 by-means of a bolt 33.15

Thevalve chamber l9 communicates withia discharge or outlet passage 34thatis adapted to jbec'onnected to a" reservoir, not shown, for re:

'ceivingthe compressed fluid. The parts 21in the seat disc; 22 establishcommunication between the valveichamber. l9 and" a passage- 35, thepurposeof'which will hereinafter appear. v

The compression cylinder-section 5 compr' es a casing 36 containingacylindrical bore 31 that is oflgreater diameter than the diameterof'the guide cylinder l6 and isadapted toreceive an enlarged head 38 ofa piston 39'having a reduced cylindrical portion engaging the guidewalloi.

the guide cylinder l6, and which is pivotally con- 7 nected to thepiston rod l5 by means-of awrist 0 pin. 7 V The head section. 6comprises a casing 4| which serves. toclose 'the end'fof the cylindricalbore 3'! and which is provided with-avalv'e chamber 30 containing aninlet disc valvedevice 42, which comprises a seat disc 43 mounted withinan openingddinrthe casing 45 andwhich is retained in operative positionby means of a cage45 that is threaded into an opening 45 in the outerwall of the casing 4|. The seatvdisc 431s provided 40 with 'aseries ofports that are adapted to be closed by means'ofa valve disc 48 thatisyieldinglyheld in engagement'with the seat disc43 by means of a spring49 that is disposed between washer 52, that issecured to the seat disc43 by means of a bolt 53; The valve chamber 30 communicates with aninlet passage 54, communicating withthe inletpassage 55in the inletsection 'l. The passage 55 may beconnected to a conduit, I 1

not-shown, through which air at atmospheric pressure is'supplied to thecompressor. Thecports 47 establish-communication between the valvechamber 39 and the bore 31 of thecompression cylinder section 5. l r 7The enlarged head 38 of the piston 39 serves to divide the bore v3'1into a compression chamber 56 on the upper side of the piston head andan annular compression chamber 51 on the under side of the piston head38, the maximum volumetric capacity of which is considerably smallerthan the maximum volumetric capacity of the compression chamber 56. Thevolumetric capacity of the chamber 5'! is maximum when the piston 39 isin its uppermost position and the volumetric capacity of the chamber 55is maximum when the piston 39 is in its lowermost posi' tion as shown inFig. l. I

The passage 35 opens into the annular co pression chamber 5? asindicated in Fig. l, and

the head 38 of the piston is provided with a ring type check valvedevice 58 which comprises a split piston ring 58 that is disposed withinan ansealing faces 52 and 53 of the groove 6| as the piston is moveddownwardly and upwardly. A series of perforations 64 establishcommunication between the groove 5! and the compression chamber Slat thelower side of the piston head 38.,

The operating cycle of a two stage compression operation of thecompressor is as follows. Assuming the, piston 38 to be in the uppermostposition, the initial downward movement of the piston moves the sealingseat E2 of the groove 5| into sealing engagement with the valve ring 59.Further downward movement of the piston creates suction within thechamber 56 andcauses air at atmospheric pressure to be drawn into thecompression chamber 56 on the upperside of the piston. During thedownward movement of the piston, the compressed fluid within the annularcompression chamber 5'! at the under side of the piston head 38, whichhas been previously forced into the chamber 51in a manner to behereinafter described, is compressed within the chamber 51 until thepressure therein overcomes the tension of the spring 29 of the dischargecheck valve device 2| and the pressure'within the valve chamber l9 andforces the valve disc 28 to open position. With the valve disc 28 open,fluid under pressure within the compression chamber 51 flows into thevalve chamber 119 and thence to; the reservoir, not shown, through thepassage 34.

Upon completion of the downward stroke of the piston 39, the spring 48ofthe intake check valve device 42 forces-the valve disc 48 into closedposition and prevents a reflux of the fluid drawn into the chamber 55through the ports 'l'pf the check valve device 52. Upon the upwardstroke of the piston 38, the sealing seat 62 of the piston groove 6! ismoved away from the valve ring 59 which is frictionally retained at restagainst the cylinder wall during the initial movement'of the piston,thereby opening communicationirom the compression chamber 56 to thecompression chamber 5'! through the ports B4 in the piston head '38.Accordingly, as the piston is moved upward the fluid'within thecompression chamber 55 is forced into the relatively smaller compressionchamber 5'! through the ports 54, thereby increasing the pressure of thefluid within the chamber'5lih accordance .with the difierence in maximumvolumetric capacity of the two chambers, it being understood that themaximum volumetric'c'apacity of the chamber 51 is considerably less thanthe maximum volumetric capacity of the chamber 56.

As before stated, upon the down stroke of the piston, when the pressureof the fluid Within the chamber 51 exceeds thatof the pressure withinthe valve chamber l9 and the reservoir associated therewith suflicientlyto overcome the tension of the spring 29, the compressed fluid is forcedinto the valve chamber l9 and into the reservoir, not shown. Upontermination of the down stroke, the valve disc 28 is closed by thespring 29 and upon the succeeding up stroke of the piston, the fluiddrawn into the chamber 56 during the down stroke of the piston will beforced into the annular compression chamber 5'! and the compressionoperation is then repeated in the manner above described.

It will be apparent from the foregoing that a compressor having a singlepiston is so constructed that fluid is compressed in two stages by thesingle piston during a single cycle of operation of the piston andconsequently the compressor may be of relatively compact construction.

Theefiiciency of the compressor is further enhanced by reason of animproved means for extracting the heat from the compressed fluid duringthe compression operation, which means comprises a system of conduitsand chambers through which cooling fluid such as water is advantageouslycirculated for obtaining maximum cooling results. The conduit systemiorthe cooling fluid includes passages 65 and 68 within the casing H of thecylinder section 4, which register respectively with passages El and 58leading from the chamber [3 disposed within the upper wall 69 of thecasing I [of the crank case section 3. The

casing 11 is also provided with two arcuate cham-- bers H on oppositesides of the guide cylinder and which communicate with the chamber [3through-openings 72 which extend through the flange 13 of the casing l'land'are aligned with openings 14 in the wall of the casing as indicatedin Figs. 1 and 2.

The compression cylinder casing of the compression cylinder sectioni isprovided with a chamber, 15 that extends partially around the bore 31and which communicates with the cham- 1 here H in the casing I! throughaligned passages 16 in the lower wall of the chamber 15 and the upperwall of the chambers H. The casing 35 is also provided with a passage Hwhich registers with the passage 65 in the casing 11.

. The headcasing 4| of the head section it is provided with an annularchamber 18 that is disposed over the end of the chamber 53 as indicatedin Fig. l and communicates with the charm ber 15'through passages 19 inthe inner wall of J.

the casing 4| and the upper wall of the chamber T5. The head casing 41is-also provided with a passage 8! which registers with the passage '5?in the casing 36 and with a passage 82 opening into a chamber 83 in thecasing of the inlet section 1 which'surrounds a portion of the passageas indicated in Fig. l.

The passage 66 in the casing l? opens into a chamber 84 which surroundsthe valve chamber 7 I9. The chamber 84 opens into an outlet passage airentering the compressor through the passage 55. The cooling fluid thenflows through passage BI, tothe passages 17 and B5 in the casings 31 andH respectively, and thence :into the annular chamber l3 in the casing,l'l, where-the cooling fluid serves to cool'a portion of-the-crankcaseand maintain the lubricant in the crank case .at a

- proper operating temperature; 7

Cooling fluid flows from the chamber 13 into the chambers 1| through theopenings 12 and thence flows through openings 16 into the chambersurrounding the cylinder bore S'L-of the casing 35. Fluid compressed bythepiston inv the compression chambers and 51 is thus cooled during theact of compression by reason of the,

through the pipe til-before it is again returned to thecompresso'rthrough the pipe 89, or the compressor maybe supplied withcooling fluid from-a water supply system, not shown, in which case thecooling fluid passing through the pipe 88 is dischargedto a drain; 7 I gFrom the foregoing it is apparent that a compact and highlyefficientcomp'ressor is provided wherein the fluid is compressed in twostages by asingle piston and wherein the air is pre cooled beforeentering the compression chamber of the compressor and'cooled during thecompression 'ope'rationfsince thewalls of the piston guide cylinder are,cooled, the temperature of the piston is maintained relatively low andtends to further cool the fluid both in the first and second stages ofcompression. Since the'temperature or-me crank case chamber 12 ismaintained relatively low due to the large bodyof cooling fluidcirculated through the chamber 13 in the upper part of the casing I I,the interior of thepiston is not subjected to relatively hot gases aswould be the case where'no provision is made. for'cooling the lubricantwithin the crank case chamber.

While 'but one embodiment of the invention is disclosed hereinandshowing a single piston two stage compressor, it isobviousthatamultiple piston compressor having more stages of compression may beembodied in a single compressor unit and that many changes, additionsand omissions may be made to the compressor construction dis"- closedwithout departing from the spirit of the invention. a 'Having nowdescribed my invention, what'I claim as new and desire to'secure byLetters Patent, is: 7

l. The combination with a compressor having a chamber a movable abutmentdividing said chamber into, compression chambers on opposite sidesrespectivelyof said abutment having unequalmaximum volumetric capacitiesand connected by a communication between the chamber'wall and theabutment through which fluid compressed by said abutment movingto reducethe volumetric capacity of the compression cham--.' her having thelarger maximum volumetric capacity is forced tothe chamber having thelesser maximum volumetric capacity, ofra ring type checkvalvecooperatingwith said abutment and Cooling fluid flows from thechamber said chamber ,wall for controlling said communication and forpreventing av reflux of the fluid flowingihrough said communication.

2. The, c,ombination with a compressor having a chambenja movableabutment dividing said chamber into compression chambers on oppositesides respectively of saidabutment having unequal maximum volumetric,capacities and cone nected by a'communication' through which fluidcompressed by said abutment'moving in one directionto reduce thevolumetric capacity of the compression chamber having the largermaximum-volumetric capacity is forced to the cham I ber'having thelesser maximum volumetric capac ity, of a valve-means cooperating with aWall of said chamber land's-aid; abutment I for controllingsaid-communication operative upon movement of said piston in theopposite; direction for preventing a reflux of the fluid flowing throughsaid communication, an intake check valve for controlling the ingress offluid to said compression chamber'having the larger maximum volumetriccapacity and an outletcheck valve for controlling the egress of, fluidfromsaidccmpression chamber having'the lesser volumetriccapacity; f

3. The-combinati'on with a compressor having a chamber,, a movableabutment "dividing said chamber into compression chambers on'oppositesides respectively of saidabutment having unequal maximum volumetriccapacitieswhichcapacities are varied upon movement of the'abutment inone direction so that as the capacity of one compression chamber isreduced, the capacity of the other compression chamber is increased,saidfcompression chambers being connected bya communication throughwhich fluid compressed by Isaidabutment moving toreduce the volumetriccapacity of the compressionchamber: having the larger maximumvolumetricicapacity is forced into ,thexchamber having the lessermaximum volumetric capacity,o-f a valve imeans cooperat ring with a wall,of said chamber and said abut ment for controlling said communicationopera tive upon movement of said piston in the. oppositedirectionforpreventing a reflux of the fluid flowing'through said communication ai 4'. The combination with a compressor having I a chamber, a movableabutment dividing said chamber into compression chambers on oppositesides respectively of said abutment havingunequalmaximum volumetriccapacities, which ca pacities arellvaried upon movement of the abutmentin one direction so that as the capacity of onev compression chamber'isreduced, the capacity of the other compression chamber is increased,said compressionchambers beingcon nected by a communication throughwhich fluid compressed by said abutmentmoving to reduce the volumetriccapacity of the compression chamher having .thelarger maximum volumetriccapacity is .forcedinto the chamber having the lessor maximum volumetriccapacity, of a valve means ecooperating with a wall of-sa-id chamberandsaid abutment for controlling saidccmmuni cation operative uponmovement of said piston in the opposite direction for'preventing areflux of the fluid flowing through said'communication, anintakecheckvalve for wcontrollingthe ingress of fluid to said compressionchamberhaving the larger maximum volumetric capacity and an out-. let checkvalve for controlling the egress of fluid fromsaid compressionchamberhaving the lesser volumetric capacity.

5. The) combination with acompressor having a Piston; cylinder, a pistonworking within said cylinder and .dividing it into chambers on oppositesides respectively of said piston, having unequal maximum volumetriccapacity and connected by a communication through which fluid compressedby said piston moving in one direction in the chamber having the largermaximum volumetric capacity is forced to the chamber having the lessermaximum volumetric capacity, of a valve means cooperating with a wall ofsaid cylinder and said piston for controlling said communication andoperative upon movement of said piston in the opposite direction forpreventing a reflux of the fluid flowing through said communication.

6. The combination with a compressor having a piston cylinder, a pistonworking within said cylinder and dividing it into chambers on oppositesides r spectively of said piston, having unequal maximum volumetriccapacity and connected by a communication between the cylinder wall ofsaid cylinder and said piston through which fluid compressed by saidpiston moving in one direction in the chamber having the larger maximumvolumetric capacity is forced to the chamber having the lesser maximumvolumetric capacity, of a valve means cooperating with a wall of saidcylinder and said piston for controlling said communication andoperative upon movemerit of said piston in the opposite direction forpreventing a reflux of the fluidflowing through said communication. 7 rI 7. The combination with a compressor having a piston cylinder, apiston working within said cylinder and dividing it into chambers onopposite sides respectively'of said piston, having unequal maximumvolumetric capacity and connected by a communication between thecylinder wall and the piston, the chamber having the larger maximum"volumetric capacity having an inlet passageand the other chamber havingan outlet passage, of an intake valve for controlling the flow of fluidthrough the inlet passage and preventing the flow of fluid from the:associated chamber through said passage, an outletvalve for controllingthe flow of fluid through the outletpassage and permitting the flow offluid therethrough from its associated chamber, and a ring type checkvalve cooperating with said cylinder wall and said piston for permittingthe flow of fluid through said communication between said chambers onlyfrom the chamber having the inlet passage to-the chamber having theoutlet passage.

8. The combination with a compressor having a piston cylinder, apistonworking within said cylinder and dividing it into a'flrst stagecompression chamber on one side of said piston and having an inlet portand a second stage compression chamber on the other side of said pistonand having an outlet port, of an inlet check valve controlling the inletport, an outlet check valve controlling the outlet port, the said pistonhaving a passage through which fluid in the first stage compressionchamber may flow to the second stage compression chamber, and a ringtype check valve for controlling said passage in the piston forpermitting fluid under pressure to flow from the first stage compressionchamber to the second stage compression chamber and operative uponmovement of the piston in one direction for preventing fluid under"pressure from flowing from the second stage compression chamber to thefirst stage compression chamber. g

9. A fluid compressor'comprising a casing hav ing a crank chamber, aguide cylinder, a comp-ression cylinder and a cylinder head, and ajacket covering walls of each of said element's-and divided intoseparate chambers, one adjacent each element and connected for providinga conduit through-which cooling fluidmay be forced for progressivelycontacting with the casing for said elementsin the order defined. Y

10. A fluid compressor comprising a casing having a fluid intakepassage, a compression cylinder, a guide cylinder, a crank chamber andan outlet passage, and a jacket covering walls of 'each of said elementsand passages and divided into separate chambers, one adjacent eachelement and connected for providing a conduit through which coolingfluidmaybe forced for progressively contacting with the casing for saidelements and passages in the order defined.

A fluid compressor comprising .a sectional casing having a crankchamber, a guide cylinder, a compression cylinder and a cylinder head,each of said elements having an integral jacket for providing a conduit,the said sections being connected together to constitute a compressorcasing and with their respective conduits in registry whereby acontinuous conduit is formed through which cooling fluidmay be forcedfor progressively contacting with the casing sections of said elements.

12. A compressor comprising a sectional casing having a compressionchamber section, a head section cooperating with one end of said.chamber section, a crank case section; and a compressor piston guidesection interposed in cooperating relation between the opposite end ofsaid chamber section and said crankcase section, the walls of saidcasingsectionshaving passageways therein respectively cooperating todirect the flow of cooling fluid in succession through said chamber"section, said guide section, said crank case section, said guidesection, said chamber section, and said head section.

l3. A compressor comprising a sectional casing having a compressionchamber section, a head section cooperating with one end of said chambersection, an intake passage section" cooperating with said head section,a crank case section, and a compressor piston'guide sectioninterposed incooperating relation between the opposite end of said chamber sectionand said crank case section, the walls of said casing sections havingpassageways therein respectively cooperating to direct the flow ofcooling fluid in succession through said intake section, said headsection, said chamber section, said guide section, said crank casesection, said guidesection, said chamber section, and said head section.

14. .A compressor comprising a sectional casing having a sectioncontaining a compression chamber adapted to have a compressor pistonoperate therein, a head-section cooperating with one end of the chambersection for closing the compression chamber and having an intake valvemechanism therein, a crank case section, and a section for guiding thecompressor piston, said guiding section being interposed in cooperatingrelation between the opposite end of said chamber section and saidcrankcase section and having a discharge valve mechanism therein, saidcasing sections having passageways therein respectively cooperating todirect the flow of cooling fluid in succession through said chambersection, said guiding section, said crank case section, said guidingsection and said head section past said intake Valve mechanism, and alsoto direct the flow of cooling fluid from said crank case section throughsaid guide section past the said discharge valve mechanism.

. BURTON S. AIKMAN.

